Why Does The Viiib Group Have 12 Elements In Periodic Table

Periodic Table: Why are group 8A elements called noble gases?

The Noble Gases are called noble because at the time they were beginning to be discovered, they would not react with any other elements. They would remain pure and untainted … noble. The noble class of people in much of Europe during (mid 1800s) had quite the ego and thought they were pure and untainted … better than the rabble surrounding them.It was these widespread cultural ideas that led to slavery, even Civil War in the US. Abuse of the middle class in America and Europe continued until unions were able to muster the might of the many and get laws passed to protect the unwashed masses from the “noble” people.Even today, people who work with iron, steel, tin, aluminum, etc (like mechanics, welders, sculptors, oilfield workers, construction workers, civil engineers, recyclers) are sometimes looked down upon stereotypically, while people who deal with more “noble” elements like neon, gold, silver (jewelers, electronics technicians, petroleum engineers, neon artists, chemists) are thought of in a higher regard.If they were discovered today, we might not choose a term that represents our politicians, leaders or clergy. There is a lot of interesting history in the periodic table. In a way it is like a map of chemistry knowledge over time and looking at old maps shows how things have changed.

What are the names of the 8 groups in the periodic table?

Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen.Snark time over. The leftmost column is the alkali metals (Li, Na, K, Rb, Cs, Fr) and the next one is sometimes called the alkaline earths (Mg, Ca, Sr, Ba, Ra). The second from right is usually called the halogens (F, Cl, Br, I, At) and the far right are the Noble gases (He, Ne, Ar, Kr, Xe, Rn).The elements in the middle, from Scandium to zinc, are typically called the transition metals. After barium comes a new group, starting with lanthanum, called the lanthanides and after Radium comes actinium, starting off the actinides.Beyond that, the columns are numbered 1–18 in a conventional Periodic Table. There’s an older naming that uses Roman numerals. The alkali metals are Group IA, the alkaline earths are IIA, then we jump over to boron for IIIA, and so on to the noble gases at VIIIA. Then we jump back over to Sc in IIIB, Ti in IIIB, and on up to Fe, Ni and Co in Group VIIIB.The logic there is that people didn’t like cramming a whole new group between Mg and Al so they telescoped the table. That did group some properties, for example the IVA (C, Si) and IVB (Ti, Zr) both tend to lose four electrons in compounds, but they otherwise have nothing in common. Here’s the old style. You hardly ever see it any more. Come on, Mn and Br together? Note they didn’t even attempt to plot the noble gases.Here’s the current style:This is a wee bit dated since all the elements with provisional (three letter) symbols have been named.You can even expand the lanthanides and actinides out, if you want.

Why is a VIIIB group of a periodic table so broad - it consists of 3 columns?

Mostly because 8 works so well for the top 2 rows.The later row numberings are just “not bad” matches to some properties for the transition metals. works OK ish in the original Mendelev table, in the extended table people didn’t create new groups just separated them into As and Bs. All the “Iron group” metals share quite a lot of properties so it works OK. Once you start to understand the physics that underly the table it becomes apparent that each column needs its own number and 8 isn’t a magic number for transition metals. What does matter is 2s electrons, 6p electrons, and then 10d electrons and how close they are in energy levels. When we add the 14f electrons we put ALL the elements filling those levels in one group so that’s even bigger.Ignore the old system and go with the modern numberings.

Which transitional metals from group 3 to 10 (the periodic table) don't have the exact number of valence electrons respectively with their group number?

Groups 3B through 10B do not have valence electrons equal to their group number.Most of the transition metals have 2 valence electrons, corresponding to the Alkaline Earth Metal that precedes them. The first row, for example, has the 4s shell on the outside. The extra electrons go into the 3rd energy level into a new set of orbitals called the d-orbitals. Since they are going into one of the inner energy levels, they don't count as valence electrons.Each level starting with the 3rd can have up to 5 d-orbitals, and each can have up to 2 electrons. That is why the transition metal block is 10 elements wide. So Scandium has 2 4s electrons, and 1 3d electron. Titanium has 2 4s electrons and 2 3d electrons.However, it gets a little murky when you get to Chromium and Copper. For some reason, Chromium and Copper only have ONE 4s electron, and therefore only ONE valence electron.Their configurations are: [math]4s^13d^5[/math] and [math]4s^13d^{10}[/math]You might be tempted to assume this pattern holds true for the other elements in groups 4B and 9B. Unfortunately, in group 4B it only holds true for the first two. In group 9B it only holds true for the first three. There is no simple explanation for this phenomenon. I'm going to offer you one, but bear in mind it's very much oversimplified. It doesn't explain why other elements in the second and third rows also do this.Basically, it appears that it takes LESS energy to put a single electron into the 5th 3d-orbital than it does to pair an electron off in the 4s orbital. The atom would rather have an even set of 3d-orbitals (one in each or two in each) than a filled 4s orbital.The following transition metals have only one valence electron:Cr, Cu (4th period)Nb, Mo, Ru, Rh, Ag (5th period)Pt, Au (6th period)Lr (7th period)Of note is Palladium (Pd), atomic number 46. Palladium has NO electrons in the 5s orbital. It actually puts them ALL into its 4d orbitals, giving it a configuration of:[math] 5s^{0}4d^{10}[/math]Weird!